Laser treatment of obstructive endobronchial tumors: factors which determine response.

To investigate whether computerized tomography (CT) and radionuclide quantitative ventilation-perfusion lung scan add any useful information to a carefully performed endoscopic examination in determining the response of patients with obstructive endobronchial tumors to laser treatment, the findings in 40 patients treated with photodynamic therapy (PDT) or the Nd:YAG laser were analysed. Endoscopic laser treatment was found to be most effective when the tumor was polypoid in appearance bronchoscopically, with little or no submucosal invasion or peribronchial extension seen on CT. When bronchoscopy and CT showed increasing submucosal and/or peribronchial disease, the immediate and long-term response to treatment was poorer. CT provided valuable information regarding the extent of the peribronchial involvement and airway distortion which were often underestimated by bronchoscopy alone. Reduction of regional perfusion out of proportion to ventilation on scintigraphy in the involved lung zone was found to be associated with extensive peribronchial involvement. We conclude that the addition of CT and radionuclide quantitative ventilation-perfusion lung scan to bronchoscopic examination is useful in predicting the response of patients with obstructive endobronchial tumors to laser treatment. Whether PDT or YAG laser is more effective in relieving endobronchial obstruction by tumor awaits a randomized controlled trial.